US3651854A

US3651854A - Canvas stretcher

Info

Publication number: US3651854A
Application number: US28187A
Authority: US
Inventors: Frederick Terna
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-04-13
Filing date: 1970-04-13
Publication date: 1972-03-28
Anticipated expiration: 1989-03-28

Abstract

A stretcher for canvas or other flexible material, the stretcher being made by miter-cutting a profiled strip into four pieces which, when assembled into a frame, have the desired stretcher dimensions. The strip, preferably fabricated of lightweight metal or plastic of high structural strength, has a uniform crosssectional profile which defines a flat outer edge, a channel fillable with a compound for accepting and retaining tacks to secure the canvas thereto, a slot for accommodating right angle irons to interconnect the pieces and a key groove to receive wedges as well as reinforcing cross bars.

Description

United States Patent Terna [4 1 Mar. 28, 1972 [541 CANVAS STRETCHER 2,149,985 3/1939 Tepper ..l60/374.l 2,167,836 8/1939 Greulich ..52/376 [72] Invent ,fififigf fifif m 89th Street 3,012,362 12/1961 Blinderman ..l60/374 1 3,392,500 7/1968 Johnston ..52/376 X [22] Filed: Apr. 13, 1970 [21] APPL NW 28,187 Primary Examiner-Darid J. Williamowsky Assistant Examiner-Philip C. Kannan Related US. Application Data Attorney-Michael Ebert [63] Continuation of Ser. No. 792,244,Jan. 21, 1969, now [57] ABSTRACT abandoned. [52] 1.1.5. C1 ..160/374.1, 52/376 A stretchgr for canvas or other flexible material the smrchcr [51] Int. Cl ..B44d 3/18 being made by miter-curling a rofiled strip imo four ieces of Search which when assembled into a frame have he desired 52/3721 3751 375 stretcher dimensions. The strip, preferably fabricated of lightweight metal or plastic of high structural strength, has a [56] References Cited uniform cross-sectional profile which defines a flat outer edge, UNITED STATES PATENTS a channel fillable with a compound for accepting and retaining tacks to secure the canvas thereto, a slot for accommodatmg 251,253 12/1881 Lazel'ges -160/374-l right angle irons to interconnect the pieces and a key groove 10/1 Tait 1 to receive wedges as we" as reinforcing cross bars. 1,847,925 3/1932 Carter ..l60/374.l 2,049,907 8/ 1936 Hess ..52/375 6 Claims, 7 Drawing Figures CANVAS ST RETCHER This is a continuation of application Ser. No. 792,244, filed Jan. 21, 1969, now abandoned.

This invention relates generally to stretching frames for supporting canvas and the like, and more particularly to a stretcher made from a profiled strip which may be miter-cut to any desired size and quickly assembled without the need for tongue and groove joints.

Conventional stretchers are constituted by a wooden frame onto which a piece of canvas or other textile material, such as silk, is marginally secured by tacks or staples. By means of wedges or screws which are forced into the corners of the frame, the material is tautly stretched in all directions across its expanse. Due to the slight give of the taut canvas under pressure of the brush, canvas stretchers afford the artist a good working surface.

It is presently the practice for art supply houses to stock pieces of molded wood whose ends are formed with complementary tongues and grooves, so that the pieces may be readily assembled into stretchers. In order to make available a broad range of stretcher sizes, it is essential for the supply house to maintain a large stock of pieces in predetermined dimensions. Usually, an art supply house must have a minimum of 37 distinct stretcher sizes if run-of-the-mill requirements are to be satisfied.

There are several practical drawbacks to the existing supply system for stretchers. There may, for example, be an unexpected demand for a particular stretcher size and, despite the large number of pieces on hand, one is yet not able to meet the need for the particular size. On the other hand, while the demand for other stretcher sizes may be infrequent, one must nevertheless have those sizes in stock in order to meet the demand when it does arise.

Hence even though an art supply house maintains a large and expensive inventory of stretcher pieces, it often finds that its inventory is inadequate in that the demand for particular sizes is erratic and unpredictable. Moreover, where the requirement is for a non-standard size, this demand cannot be met at all and the artist must arrange to have the stretcher custom-made.

With the present tendency in the art world for artists to work on very large-scale canvases, existing stretcher inventories are incapable of providing the required dimensions and many artists are forced to improvise their own stretchers. Unless a stretcher is professionally made, the stretcher will not hold its proper form, and warpage, twisting, corner mismatch and change of angle are experienced which have damaging effects on the painting. Existing stock stretchers have no provision for cross pieces to reinforce the structure to maintain its proper configuration.

It is not possible, in place of precut pieces, merely to have an inventory of long strips which can be miter-cut to size when an order is received, for it is also necessary with a conventional stretcher to have tongue and groove joints. It is neither practical nor feasible in an art supply house to install equipment for cutting tongues and grooves, which is the reason for the present practice of stocking factory precut pieces which incorporate these formations.

Accordingly, it is the main object of the present invention to provide a profiled strip which may easily be cut into pieces of any desired size to form a stretcher without the need for tongue and groove joints.

Also an object of the invention is to provide a profiled strip of the above type which may be fabricated of lightweight metal or plastic which is free of warpage, dimensional instability and other drawbacks characteristic of wood. It is to be understood, however, that the profiled strip in accordance with the invention may be made of wood and still have advantages over conventional wood stretchers.

Yet another object of the invention is to provide a stretcher which may be manufactured and sold at relatively low cost, and which requires relatively little skill to assemble properly.

A significant feature of the invention is that substantially it reduces inventory requirements for art supply houses, for by stocking standardized strips of the profiled material, one may supply an artist with a stretcher of any specified size without the need to stock a broad range of precut pieces. Moreover, one may supply non-standard as well as standard stretcher sizes so that the artist is not limited in his work to existing stretcher dimensions.

Briefly stated, these objects are accomplished by a profiled strip whose uniform cross-sectional shape defines a flat outer edge which forms the border of the stretcher, a back channel which is fillable with a compound for accepting tacks to secure the canvas thereto, a front slot to accommodate right angle irons to join the pieces of the stretcher, and an inner key groove to receive stretching wedges as well as reinforcing cross bars.

For a better understanding of the invention, as well as other objects and further features thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawing wherein:

FIG. 1 is a perspective front view of a stretcher in accordance with the invention,

FIG. 2 is a transverse section taken in the plane indicated by lines 22 in FIG. 1,

FIG. 3 is an exploded view of two pieces of the stretcher,

FIG. 4 is a plan view showing one corner of the stretcher, with the canvas cut away to expose a stretching wedge,

FIG. 5 is a perspective rear view of the stretcher, showing the reinforcing cross bars therefor,

FIG. 6 shows, in exploded view, the manner in which one cross bar is interfitted with another cross bar, and

FIG. 7 shows the manner in which a cross bar is interfitted with a stretcher piece.

Referring now to the drawing and more particularly to FIGS. 1, 2 and 3, there is shown a stretcher in accordance with the invention which is created by miter-cutting a strip of profiled material into four stretcher pieces 10, ll, 12 and 13 which, when joined together, form a rectangular frame of the desired size. The ends of the pieces are miter-cut at 45 so that when joined together, right angle corners are formed in the usual manner.

The profiled strip from which the pieces are cut may be made of extruded aluminum or other lightweight material which is structurally stable and of high strength. The crosssectional profile of the strip, which can best be seen in piece 13 in FIG. 3, is uniform such as to define a flat longitudinal edge A, a rear channel B, a front slot C and an inner key groove D, the channel slot and groove all lying in parallel relation to the edge. Edge A forms the border of the stretcher frame over which is placed a piece of canvas 14 or other paintable, flexible material such as silk or paper.

The margins of canvas 14 are carried over flat edge A to overlie the back channel B. Channel B is filled with a suitable compound such as plastic wood, foam plastic or any other composition capable of accepting and retaining tacks or staples or whatever other means are used to secure the canvas to the stretcher. In FIG. 2, it will be seen that the canvas is attached to the stretcher by tacks 15.

The flat edge A of the strip projects well above the body thereof, as best seen in FIG. 2, to space the canvas 14 therefrom. Inasmuch as the stretched canvas, when subjected to brush pressure, gives somewhat, this spacing acts to prevent the canvas from engaging the body of the stretcher pieces, and thereby prevents the formation of undesirable ridge marks on the painted canvas.

Slot C is dimensioned to receive a right angle iron 16, as shown in FIG. 3, one leg of the iron going into slot C of piece 13 and the other in slot C in piece 10 to join these pieces together, thereby obviating the need for a tongue and groove connection. The angle irons initially provide a loose connection of the pieces, but when the canvas is attached, the pieces are securely held together.

After the canvas is marginally secured to the stretcher, it is necessary to stretch the surface thereof in all directions across its expanse. For this purpose, as shown in FIG. 3, wedges l7 are driven into the corners of the pieces through the key grooves D. As will later be explained, these grooves have a "T shaped configuration defining a deep minor groove and a broader major groove to accommodate cross pieces as well as the wedges. To facilitate the wedging action, the grooves D, at the corners of the minor grooves, may be beveled to form an entrance d into the corner junction. As the wedges are driven in, the joined pieces tend to separate, thereby subjecting the canvas to tension. When the pieces separate, they still maintain their proper right anglerelationship, for the angle irons in slot C prevent angular displacement of the pieces.

As shown in FIG. 5, the stretcher may be reinforced by cross pieces to prevent bowing thereof or other undesirable dimensional changes. Such reinforcement is generally only necessary in larger stretcher sizes. In the fairly elaborate arrangement shown,

vertical cross pieces

18 and 19 are interposed between the stretcher pieces and 12, while horizontal cross piece 20 is interposed between stretcher piece 11 and cross piece 18, horizontal cross piece 21 is interposed between cross piece 18 and cross piece 19, and cross piece 22 is interposed between cross piece 19 and stretcher piece 11, thereby providing an intersecting reinforcement pattern of high strength.

As illustrated in FIGS. 6 and 7, each cross piece, such as 18, has a rectangular cross-sectional form, with channels C and C cut into the opposing long sides thereof. The width of channels C and C in the long sides is equal to the length of the short sides of the cross piece, thereby making it possible for the end of cross piece 21 to be inserted in channel C of cross piece 18, as shown in FIG. 6. Channels C and C are each formed with a depressed subchannel to receive a wedge 17 to hold an inserted cross piece in place.

, The widthof the key groove'D in the stretcher piece 10, as shown in FIG. 7, is equal to the length of the long sides of the cross pieces, so that the end of cross piece 18 may be inserted therein and locked in place by wedges 17.

It is to be understood that the strip according to the invention is not limited to the particular profile shown and that while in all cases the strip must have a flat outer edge to provide the border, the placement and configuration of the channel' B for the compound,the slot C for the angle irons and the key groove for the stretching wedges may be varied to suit the use to what the stretcher is to be put.

It will be evident from the foregoing, that all the art supply house need store is a stock of long profiled strips in any suitable standard size, and strips of cross piece material, and when an order for a particular stretcher dimension is received, it is only necessary to cut the strips into pieces of the requisite size.

Thus while the stretcher has been disclosed herein as intended for canvas, it is usable also with silk screens and watercolor paper as well as with materials having a more limited stretch, such as leather, cardboard and metal foil. The channel vB for the tack-receiving compound need not be on the back of the pieces, and may in some instances be formed in border A on the front side thereof, this arrangement being useful for silk screen s.

I claim: 1. A stretcher for a canvas or other flexible material, said stretcher comprising:

' A. four side pieces which are miter-cut from a profiled strip of block material to form a rectangular frame to support said canvas, said strip having a cross-sectional profile 4 which is uniform throughout its length and is contoured to define the following elements extending the full length of the strip;

a. a flat outer edge forming the border of the stretcher,

b. a channel fillable with a compound for accepting and retaining tacks or other means to secure the margin of the canvas thereto,

0. a slot for receiving right angle elements, and

d. a key groove having a T-formation defining a depressed minor groove to receive wedges and a broader major groove to receive the ends of cross pieces whose width is substantially the same as the width of the major groove,

B. four right angle elements inserted in the slots of said pieces to interconnect same to form the corners of the stretcher,

C. at least one cross piece extending between opposed side pieces of the stretcher, the ends of said cross piece being received within the major grooves of said side pieces, and

D. wedges inserted in the minor grooves of the side pieces at the corners of the stretcher to tension the canvas supported thereon, and inserted in the minor grooves of. the side pieces adjacent the ends of said cross piece to secure the cross piece thereto.

2. A stretcher as set forth in claim 1, wherein said edge, said channel, said slot and said groove all lie in parallel relation,

said channel being at the back of the strip and said slot at th front thereof.

3. A stretcher as set forth in claim 1, wherein said compound has wood-like characteristics.

4. A stretcher as set forth in claim 1, wherein said strip is formed of extruded aluminum.

5. A stretcher as set forth in claim 1, wherein said flat edge is dimensioned to space the canvas secured to said stretcher away from the body of said pieces.

6. A stretcher for a canvas or other flexible material,.said stretcher comprising:

A. four side pieces which are miter-cut from a profiled strip of block material to form a rectangular frame to support said canvas, said strip having a cross-sectional profile which is uniform throughout its length and is contoured to define the following elements extending the full length of the strip;

a. a fiat outer edge forming the border of the stretcher,

b. a slot for receiving right angle elements, and

c. a key groove having a T-formation defining a depressed minor groove to receive wedges and a broader major groove to receive the ends of cross pieces whose width is substantially the same as the width of the major groove,

C. at least one cross piece extending between opposed side pieces of the stretcher, the ends of said cross piece being received within the major grooves of said pieces, and

D. wedges inserted in the minor grooves of the side pieces at the corners of the stretcher to tension the canvas supported thereon, and inserted in the minor. grooves of the the cross piece thereto.

Claims

1. A stretcher for a canvas or other flexible material, said stretcher comprising: A. four side pieces which are miter-cut from a profiled strip of block material to form a rectangular frame to support said canvas, said strip having a cross-sectional profile which is uniform throughout its length and is contoured to define the following elements extending the full length of the strip; a. a flat outer edge forming the border of the stretcher, b. a channel fillable with a compound for accepting and retaining tacks or other means to secure the margin of the canvas thereto, c. a slot for receiving right angle elements, and d. a key groove having a T-formation defining a depressed minor groove to receive wedges and a broader major groove to receive the ends of cross pieces whose width is substantially the same as the width of the major groove, B. four right angle elements inserted in the slots of said pieces to interconnect same to form the corners of the stretcher, C. at least one cross piece extending between opposed side pieces of the stretcher, the ends of said cross piece being received within the major grooves of said side pieces, and D. wedges inserted in the minor grooves of the side pieces at the corners of the stretcher to tension the canvas supported thereon, and inserted in the minor grooves of the side pieces adjacent the ends of said cross piece to secure the cross piece thereto.

2. A stretcher as set forth in claim 1, wherein said edge, said channel, said slot and said groove all lie in parallel relation, said channel being at the back of the strip and said slot at the front thereof.

6. A stretcher for a canvas or other flexible material, said stretcher comprising: A. four side pieces which are miter-cut from a profiled strip of block material to form a rectangular frame to support said canvas, said strip having a cross-sectional profile which is uniform throughout its length and is contoured to define the following elements extending the full length of the strip; a. a flat outer edge forming the border of the stretcher, b. a slot for receiving right angle elements, and c. a key groove having a T-formation defining a depressed minor groove to receive wedges and a broader major groove to receive the ends of cross pieces whose width is substantially the same as the width of the major groove, B. four right angle elements inserted in the slots of said pieces to interconnect same to form the corners of the stretcher, C. at least one cross piece extending between opposed side pieces of the stretcher, the ends of said cross piece being received within the majoR grooves of said pieces, and D. wedges inserted in the minor grooves of the side pieces at the corners of the stretcher to tension the canvas supported thereon, and inserted in the minor grooves of the side pieces adjacent the ends of said cross piece to secure the cross piece thereto.